(Portland, Oregon) – Seeing them in Portland, around the inland state and the Oregon coast may be a challenge through cloud layers, but they are indeed whizzing overhead. The Lyrid meteor showers are reaching their height tonight and tomorrow night (Thursday), and Oregon and the West Coast have a front row seat to a lot of trails in the sky. (Above: Lincoln City at night on Saturday night).
Jim Todd, director of space education at Portland’s OMSI, said every year in late April the Earth passes through the dusty tail of Comet Thatcher (C/1861 G1), and the encounter causes a meteor shower – the Lyrids. They are also known for creating rather unusual surges that can bring as many as 100 shooting stars a minute.
“Those rare outbursts are not easy to predict, but they’re one of the reasons the tantalizing Lyrids are worth checking out,” Todd said. “The radiant for this shower is in the constellation Lyra, which rises in the northeast at about 10 p.m.. According to NASA, the shower will peak on April 22-23 with 10 to 20 meteors per hour. The waxing crescent moon will be out of the way in the early evening. Sky watchers are already seeing some early arrivals.”
Todd said these little darts of lights appear to come from the bright star Vega in the constellation Lyra. However, they are actually flakes of comet dust from Comet Thatcher. Most are no bigger than grains of sand, which smack the the Earth’s atmosphere at some 110,000 mph and then disintegrate as streaks of light.
“Lyrid meteors are typically as bright as the stars in the Big Dipper, which is to say of middling brightness,” Todd said. “But some are more intense, even brighter than Venus. These ‘Lyrid fireballs’ cast shadows for a split second and leave behind smoky debris trails that linger for minutes.”
Occasionally, the shower intensifies, he added. Most years in April there are no more than 5 to 20 meteors per hour during the shower’s peak. But sometimes, when Earth glides through an unusually dense clump of comet debris, the rate increases. Sky watchers in 1982, for instance, counted 90 Lyrids per hour.
Todd suggests the following strategy for spotting these:
Dress warmly. Bring a reclining chair, or spread a thick blanket over a flat spot of ground. Lie down and look up somewhat toward the east. Meteors can appear in any part of the sky, although their trails will tend to point back toward the radiant – i.e., toward Vega. It is a brilliant blue-white star about three times wider than our Sun and 25 light years away.
“You might have seen Vega in Carl Sagan’s movie Contact. It was the source of alien radio transmissions to Earth,” Todd said.
The constellation Lyra the Harp will appear to be the radiant point for the shower. Those of us in the northern hemisphere will see Lyra rise over the north-northeastern horizon around 10 to 11 p.m..
However, Todd said you don’t actually have to know how to identify Lyra – or even know its direction in the sky – to see a meteor in this annual shower. Meteors often don’t become visible until they are 30 degrees or so from their radiant point. In other words, the meteors will appear in any and all parts of the sky after Lyra ascends over the horizon in late evening.
A camera, provided by scientists at NASA’s Marshall Space Flight Center, will offer a live feed of the Lyrids beginning at 8:00 PM PDT. The camera is light-activated, and will switch on at nightfall. During daytime hours, the webcast will show recorded views of past meteor showers.The live feed is at: http://www.ustream.tv/channel/nasa-msfc.
Weather will be the real issue for the Oregon coast, which can be a bit hazy due to ocean mist. But tonight and tomorrow are forecast to be mostly clear at night. For Portland, increasing clouds later are in the works, but some visibility should still be possible.